Nicotine base is a reactive species which decomposes in the presence of oxygen or light. It is highly hygroscopic. Nicotine base causes the solvation of standard adhesives, which cannot be effectively used to seal nicotine-containing pouches.
The problem of providing containment for consumer products containing nicotine base has heretofore found no simple solution. A transdermal system for the delivery of nicotine is disclosed in Australian Patent Application Au-A-81454/87. In that system two nicotine precursors are sealed in burstable pouches. Only after application to skin and rupture of the pouches is the highly reactive nicotine base formed.
It is very desirable to provide a container which can hold one or more nicotine-containing devices. Such a container must be inert to nicotine; that is, it must not cause degradation of nicotine base, or be degraded by nicotine. The container must act as a barrier to nicotine. A nicotine barrier permits less than 1% nicotine migration over a period of six months, more preferably less than 0.5% migration, and most preferably is impermeable to nicotine. Because nicotine acts as a solvent to standard adhesives, the barrier material must be sealable to itself, such as by heatsealing. The seal must provide a stable bond which does not provide a path for nicotine migration out of the package.
The container must also act to exclude agents which are detrimental to the stability of nicotine base. Air (oxygen) and light both act to decompose nicotine base. In addition, nicotine is strongly hygroscopic, and water in liquid or vapor form will be adsorbed into the nicotine base, causing a change in nicotine concentration.
Materials which provide a barrier to nicotine and provide protection from nicotine degradation agents include metal foils such as aluminum foil, polyesters such as polyethylene terephthalate (PET), and poly(tetrafluorethylene) (PTFE). These materials are not self-sealable, and adhesive or heat sealable coatings on the surface of these materials can provide a path for migration of nicotine out of the package. Traditional self-sealable pouching materials such as polyvinyl fluoride (PVF), polyvinylidene fluoride (PVDF), chlorotrifluoroethylene (CTFE), low density polyethylene (LDPE), and high density polyethylene (HDPE) do not provide an effective nicotine barrier.
We have unexpectedly discovered that nitrile rubber modified acrylonitrile-methyl acrylate copolymers of the type, commercially available as BAREX.TM., can be used as a heat sealable material in pouches to provide an effective barrier to nicotine migration even over extended periods of time.
It is therefore an object of this invention to provide a container for nicotine base or for products containing nicotine base.
It is an object of this invention to provide a self-sealable, pouchable material which acts as a barrier to nicotine.
It is another object of the invention to provide a pouching material which acts as a barrier to nicotine degradation agents such as air (oxygen), water in liquid or vapor form, and light.
It is yet another object of the invention to provide a pouch which is suitable for long-term containment of nicotine-containing transdermal delivery devices.